+1. Whenever I have seen a decent band in a bar or small venue, I always know who's in the band before they come onstage because they look bandish (not a word I'm sure). The band should always look like what they are: professionals (however casual the venue, even if you're not being paid your still doing a job), whereas the crowd can look like they don't care. It seems a shame that people in a band can be creative musicians and not with their clothes. Shallow as it sounds, I'd like it if people made the effort all the time so the world looked a bit more creative and just better.a bartender once told me always dress one step above the people you are serving.
If they are in flip flops and tank tops, your in shoes and a t-shirt, if they are In shoes and tee shirts you are in a polo shirt, etc.
Last night I played a private party (christmas dinner) with a $75 cover, everybody in the crowd was in formal dresses and dinner jackets. We all wore dress shirts and ties with jackets, of course by the end of the night my tie was around my head like RAMBO, but at least we started out on par with the crowd.
Today I'm playing a toy drive show at a honky tonk bar, It will surely be come as you are, but I will probably wear a western shirt untucked with jeans and nice shoes/boots.
Dressing nice really helps your band to look like a band. It helps you to meet audience expectations, and it shows you take your music seriously. If you show up looking sloppy why should people care what you are doing on stage?
I'm a professional musician so in my situation buying outfits for playing a show is a tax deduction. It's helped me to justify having "show clothes" and get into dressing up.
I had a turning point one time there was pictures of me with the road crew after a big gig. I was wearing a t-shirt, cut off army pants, and doc martens. Honestly you couldn't tell the difference between me and the roadies. I realized then I have to start looking like a musician.